Underreamer.



Patented J an. 3, 1911.

N `0 S R E T E D.. L,

UNDERREAMER.

A'PPLIOATION FILED MAR.28, 1910.

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r I l l Attorneys UNITED STATES 4ririnNT OFFICE.

BERT L. PETERSON, OF ROBINSON, ILLINOIS.

UNDERREAMER.

Specification of Letters Patent.

Patented Jan. 3 1911 Application filed March 28, 1910. Serial No. 551,992.

To (IZZ 'who-m fit 'may conce-rn:

Be it known that I, Beitr L. Pirrsiisox, a

Vcitizen ot' the lnitcd States. residing at this is usually doiie'by enlarging Vthe hole below the casing suiliciently so that the eas:- ing may be lowered, thehole being thus coutinued to the desired depth. This operation is known as uiiderreaming. and the invention relates to a tool for performing this operation, the `tool being` of that type in `which the slips or cutters expand when they clear the lower end of the casing.

It is the object of the invention to provide an underreainer of the kind stated which is strong and durable, and also simple in construction, tlie number of parts being reduced to a minimum, so as to eliminate as much as'possible, screw and other joints, which are objectionable by reason of their liability to become separated when the tool is in use.

The invention also has for its object to provide improved means for supporting and reinforcing the slips or cutters, so that they may successfully withstand the strain which is placed on them when at work.

W'it-h these objects in view, the invention consists in a novel construction and arrangement of parts to'be hereinafter described and claimed, reference beingI had to the acstock of the tool, which is formed at its upper end with anexteriorly threaded portion 6 for uniting with the other ltools of the string in a manner Well known in the art. The stock is preferably cylindrical in form, and has at its lower end a' cylindrical socket 7 to receive the up er ends of the slips to be presently described). The stock also has `a central longitudinal bore 8 which'is closed :it one of its ends, and opensat its other end into the socket 7. Into the last mentioned end of vthc'bore is screwed ya bushing 9. Through this bushiiiof extends a rod 10. one end of which passes into the bore S. and the other end ot' the rod extends into the socket 7. The last mentioned portion of the rod 'carries a transverse key 11 which )rejects from opposite sides thereof. The unction of this key will be presently described. The end of that. portion of the rod which is 1ocated in the bore is reduced and screw threaded to receive a Vnut l2 which screws down on the shoulder formed by said reduced portion. The nut is locked by a cotter 13. In the bore is located a coiled spring 14, said s )ring being 'coiled around the rod between the bushing!) sind the nut At 15 are indicated the slips or cutters of the tool. The bottom of each slip is inclined to forni a cutting edge 1G. The slips extend to be expanded `or contracted as will be res' ently described. The opposite faces o the upper portions of the slips are grooved as indicated at 18 to permit the, rod to come therebetween.

Extending across the socket '7, adjacent to its lower end, is across bar 19,said cross bar being wedge shaped in cross section at its lower end. The cross bar is located be-V tween the slips below the point of attachment of said slips to the rod 10. The innerfaces of the slips are formed with notches Q0, these notches, being opposite each other, and when theslips come to ether, forming arecess to receive the cross ai 19. Below this recess the inner faces of the slips are straight` for a short distance as indicated at 21, and beyond the saine, said faces are inclined-in opposite directions, as indicated at 2:2, to

y forina space between the slips which istapered in the 'direction .of the cross bar. The

recess formed by the notches .20. tapers in 'los the direction of the portions 21'.

The outer surface of each slip is fo/rined with a shoulder 23 having an upper portion 24 which is adapt to 'come squarely 4against:

the lower end of the stock 'when the slips-film 'are in working position alsshown in Fig. 2,

and beyond this portion of the shoulder-,the

saine isbeveled4 as indicated at 25..

liso-ij.

Fig'. 1 shows the position of the parts as the tool is being run down the well casing 26. The slips have been retracted so that theymay pass through the casing. This is v5 done'by pulling said slips downwardly until the cross bar 19 comes into the recessformed by the notches 20. The outer surfaces of the shoulders v23 are in Contact with the inner surface of the casing, whereby the thus increase the `frictional Contact between ."fthe shoulders 225, and the casing` wall. This tendency of the slips-to spread is produced by the cross bar 19. YVhen the shoulders 23 clear the lower end of the casing 26, the slips `'re released, andv they spread as shown in A 'Fig'. 2, and thus come into operative posi- ",tion. It will,-.of course, be understood, that before placing the tool in operative position, 'the casi11g 26 is raised-a short distance in ,'30 order that lthe reamin may start at the shoulder 27' `which originally supported the casing.v fWhen. the slips spread out as stated, their points 16 extend outwardly suiiciently to make-a hole -having the same diameter as the original hole. v The, moment the shoulf'ders 23 clear the lower end of the easing 26 ,fthe spring 2L1 is .permitted to expand, and ,it pulls the'slipsl upwardly until the portion ofthe shoulders engages the lower end 40 ot' the stock 5. W'hen tle slips move upwardly, the cross bar 19 enters between the portions 2l of the slips, and thus causes said 'slips" to spr ead outas stated. The entry of the crossb'ar between this portion of the slips 4is facilitated by its 'wedge shape, as well fas by; the'- tapered portion of the recess formed vby the notches 20.v It will be noted 'i i' that the space between the portions 21 of the is slightly tapered in the direction of the liecesswhen' vthe slips are in retracted po- "fsition,'andthevpointof the wedge shaped portion of the cross-bar extends into this i ilared portionof the space. When the slips arein workifng position, as shown in Fig. 2,

their upper ends are in contact with the uper eid ofthe socket?, land with the bush- 1ngl9, That-portionof the slips which extends into the sockets is shaped to fit snugly The entire upper. e1 1 ds` lof the slips ar re re backed, h, nwith lthe en- 'l Q ,the shoulders .with 'the lower fwould'tend to spread them still further, and

end of the stock 5 sustains the thrust and strain on the slips when in operation. The slips are thus rmly supported, and they will successfully withstand the heavy strain to which they are subjected when in operation. The shoulders 23 extend substantially around the full circumference of the slips, Rotation of the slips in the stock is prevented by the cross bar 19.

To withdraw the tool, the stock 5 is pulled upwardly until the shoulders 23 engage the lower end. of the casing 26. A continued pull on the stock, elevates the stock with respect to the slips, and the cross bar 19 enters the recess formed by the notches 20. As the cross bar enters this recess, the slips come together so that they may enter the casino 26, the parts now again assuming the position Shown in Fig. 1. The bevels 25 engage the lower edge of the casing, and force the slips inwardly as the cross bar enters the recess.

By the structure herein described, an underaming tool is had which is strong and durable, and also simple in construction, it beingv entirely devoid of complicated parts. The number of parts is also reduced to a minimum, and said parts are so connected that there is no danger of the same becoming separated. The key 11 passes through the rod 10 and the slips only, and as it is located within the socket 7, it is held in position, and cannot slip out while the tool is in use. The bushing 9 permits the spring 14 to be placed in position from the lower end of the stock, thus avoiding screw joints at its upper end.

An underreamer comprising a stock having an end socket, slips mounted in the socket, and having their cutting portions projecting therefrom, at support for the slips carried by the stock, said support being connected to the portions of the slips which are located` within the socket, and said support permitting a 'sliding and spreading movementof theslips, and a cross bar carried by the stock, said cross bar being locate-din' the end socket between the portions ofthe slips extending thereinto, the opposite -faces of said port-ions being recessed to receive the cross bar,.and said cross bar being wedge shaped in cross section to spreadthe slips when it passes out of the recesses.

In testimony that I claim the foregoing as 'my own, I have hereto atlixed my signature inthe presence of two witnesses.

' BERT L.l PETERSON.

Witnesses: GEORGED. MCCARTY,

' JOHN Korir.' 

